<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>03_总结各元素的显示模式</title>
    <style>
        #s1 {
            background-color: skyblue;
        }
        #d2 {
            background-color: orange;
        }
    </style>
</head>
<body>
    <span id="s1">123</span><br><br>
    <div id="d2">456</div>
</body>
</html>